Neural mechanisms underlying vocal learning in the songbird

鸣禽发声学习的神经机制 已知的运动序列是大多数人类交流的基础，但令人惊讶的是，人们对此知之甚少 神经系统如何学会控制复杂的肌肉动作。我们的长期目标是 描述习得运动行为的神经回路机制。这个 斑马雀，一种鸣禽，提供了一个独特的系统来追求这个目标，因为它在 这与我们学习包括语言在内的许多运动技能的方式大致相同。 目标：我们的提案旨在描述歌曲的运动程序是如何通过录制 自由活动的幼年斑雀运动皮质类似结构(RA核)中的神经元 贯穿歌曲学习(目标1)。被广泛认为是声乐学习的场所，RA收到了 来自高阶运动区、HVC和基底节回路的会聚输入。这项建议 我将研究这两个输入在形成RA运动指令过程中的各自作用 学习(目标2)。我们考察了基于听觉反馈的绩效评估，这是一个至关重要的 歌曲学习和歌曲维护的成分，影响运动的发展 方案(目标3)。最后，我们评估学习引起RA运动变化的程度 程序是由HVC的变化驱动的，它的前置电机输入(目标4)。 方法：该提案将结合强大的方法来研究这些问题：定制- 制作的电动微型驱动器将允许记录单个神经元在歌唱中的RA，少年 和长期植入的反向微透析装置将使快速和可逆成为可能 基底节环路失活。最后，我们将使用包含我们的 观察到一个生物物理学上看似合理的模型，说明歌曲回路是如何学习和运作的。 相关性：我们的实验旨在描述复杂马达背后的运动程序 行为的进化，以及作为其基础的马达电路相对于 学习。产生发声的神经回路之间的同源和类比 鸣禽和人类很多，因此我们的发现也将说明马达是如何 可以获得潜在的语音和其他习得的运动行为的程序。了解 复杂运动学习的神经关联将使我们能够准确定位这一过程可能失败的原因，因此 解决各种运动障碍和残疾的可能原因。

Neural mechanisms underlying vocal learning in the songbird Learned motor sequences underlie most of human communication, yet remarkably little is known about how the nervous system learns to control the complex muscle actions involved. Our long term goal is to describe the neural circuit mechanisms underlying the acquisition of learned motor behaviors. The zebra finch, a songbird, provides a unique system in which to pursue this goal, as it acquires its song in much the same way that we learn many of our motor skills, including speech. Aims: Our proposal aims to describe how the motor program for song develops by recording from neurons in a motor cortex analogue structure (nucleus RA) in the freely behaving, juvenile zebra finch throughout song learning (Aim 1). Widely thought to be the site of vocal learning, RA receives convergent input from a higher order motor area, HVC, and from a basal ganglia circuit. The proposal will examine the respective roles of these two inputs in shaping the motor command in RA during learning (Aim 2). We examine how auditory feedback-based performance evaluation, a crucial ingredient for both song learning and song maintenance, influences the development of the motor program (Aim 3). Lastly, we assess the extent to which the learning induced changes in the RA motor program are driven by changes in HVC, its premotor input (Aim 4). Methods: The proposal will examine these issues with a combination of powerful methods: custom- made motorized microdrives will allow the recording of single neurons in RA in the singing, juvenile bird, and a chronically implanted reverse microdialysis device will make possible the fast and reversible inactivation of the basal ganglia circuit. Finally, we will use mathematical models that incorporate our observations into a biophysically plausible model of how the song circuit learns and functions. Relevance: Our experiments aim to describe how the motor program underlying a complex motor behavior evolves, and the logic by which the motor circuits underlying it are organized with respect to learning. The homologies and analogies between the neural circuits generating vocalizations in songbirds and humans are many, thus our findings will also speak to the question of how the motor program underlying speech and other learned motor behaviors may be acquired. Understanding the neural correlates of complex motor learning will allow us to pinpoint how the process may fail, thus addressing the possible causes of various motor disorders and disabilities.